Mailings using Crystal Clear Bags may be used and tested for any weight up to: 13 ounces for First-Class Mail, 20 ounces for Periodicals, less than 16 ounces for Standard Mail, and 20 ounces for Bound Printed Matter.
What envelope is 9x12?
COMMON ENVELOPE NAME STANDARD SIZE MAXIMUM ENCLOSURE SIZE
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6 x 9 envelope 6 x 9 inches 5-3/4 x 8-3/4 inches
9 x 12 envelope 9 x 12 inches 8-3/4 x 11-3/4 inches
10 x 13 envelope 10 x 13 inches 9-3/4 x 12-3/4 inches